I take it that is in the complex plane. Taking the x-axis to be the real line and the y-axis to be the imaginary line, x= t^2- 1 and y= t+ 4. From y= t+ 4, t= y- 4. Replacing t in the x equation with that, x= (y-4)^2- 1. That's a parabola with horizontal axis. Can you graph that? Where is the vertex?